(1) Field of the Invention
The present invention relates to a device for unloading bulk material from a vehicle, and more particularly to a device for unloading bulk material from a live-floor vehicle.
(2) Description of the Related Art
Bulk material is known within the art as being any uncontained solid matter that has the capability of becoming airborne or creating fugitive dust. For example, bulk materials can include mulch, wood chips, dirt, sand, gravel, clippings, leaves, livestock feed, fertilizer, manure, hay, seed, compost, construction debris, plastic pellets or powders, grain, minerals, cement, gypsum, aggregate, clinker, gypsum, limestone, salt, coal, or soils.
A common piece of equipment used in the course of transporting bulk material is a live-floor trailer. These self-unloading trailers typically have a moving floor that can push bulk material contained within the vehicle toward some outlet on the trailer and out onto the ground.
Many live-floor systems utilize a series of hydraulically actuated floor slats and a drive unit. For example, the Walking Floor® is a live-floor system available from KEITH® Manufacturing, located in Madras, Oreg. In this system, the floor slats are horizontally-placed, moving in a forward-to-backward motion. The drive unit, which is usually mounted beneath the floor, powers the slats through a three-phase cycle to convey the material. In each of the first two phases, one-third of the slats move while the remaining two-thirds remain in place. During these two cycles, the bulk material does not move. In the final cycle, all the slats move together to convey the load toward the outlet, which is typically the rear of the vehicle.
U.S. Pat. No. 3,483,717 discloses a self-unloading trailer with an endless conveyor belt overlying the floor of the vehicle. The conveyor belt rides on the floor and is further supported and driven by a roller at each end of the trailer. Means are provided for turning the rollers in the same direction at the same speed. The endless conveyor belt allows the material within the trailer to be supported on the belt and transferred out of the trailer through the tailgate.
Another moving floor system consists of a series of slats connected to endless conveyor chains. The revolving floor system, discussed in U.S. Pat. No. 4,505,634 to Rezac, provides a flat bed trailer with the option of having either a live-floor configuration or a stationary configuration. If the live-floor is desired, the endless chains are rotated until the portion of the conveyor chains having the slats attached thereto is positioned over the top surface of the trailer bed. Material is then loaded onto the slats and the chains are rotated to empty the material from the vehicle. If the stationary floor is desired, the endless chains are rotated until the portion of the conveyor chains having the slats attached thereto is positioned along the bottom surface of the trailer bed.
While these systems are effective in moving bulk material toward the outlet of the transport vehicle and onto the ground, it is often necessary to convey the bulk material to a level that is higher than the outlet of the vehicle. Several devices have emerged which respond to that need.
For example, U.S. Pat. No. 2,609,115 to Oklehas discloses a self-unloading conveyor mechanism that is mounted to a truck. The truck has a tapered hopper body and a drag conveyor on its floor. The auxiliary discharge conveyor has a telescoping design.
U.S. Pat. No. 2,834,487 to Gaddis discloses a folding belt conveyor that is attached to a truck which has a tapered hopper body. The self-contained, mobile structure unloads and elevates bulk material.
U.S. Pat. No. 3,521,767 to Rossi describes a deployable belt conveyor for a cement mixer-type truck body. The conveyor can be rotated about a shifting vertical pivot axis and locked in place to deliver the material to the desired location.
U.S. Pat. No. 3,923,175 to Landvatter describes a hitch for a portable conveyor. The conveyor can be hitched to the back of a dump truck to accept material that is dumped into it and convey it upwardly and/or outwardly from the truck.
U.S. Pat. No. 4,072,242 to Cook describes a self-unloading forage wagon having a tailgate that is fitted with a conveyor mechanism that permits dumping of the load over the entire width of the bed when the tailgate is lowered.
U.S. Pat. No. 5,443,351 to Pettijohn discloses a mobile hydraulic conveyor that can be mounted on the back of a dump truck, for example, to accept material from the bed of the truck and convey it outwardly.
While these and other bulk material handling systems are useful and sufficient for many applications, a common disadvantage is that the only way to unload bulk material from the vehicle while the conveyor device is attached to the vehicle is through use of the conveyor. The prior art devices fail to provide a method for unloading the vehicle through use of the live floor alone, without actual use of the conveyor device. The prior art devices must be physically removed from the frame of the vehicle in order to unload the vehicle solely by use of the live-floor.
Removing the device from the vehicle requires a significant time commitment and requires certain tools, equipment, and manpower to aid in the removal. This can become a significant impediment if the vehicle is required to drive to several locations, using the conveyor to elevate and convey material in some of those locations and using the live floor to dump material in other locations. Accordingly, there remains a need for an unloading device for a live-floor vehicle, wherein the device will allow the bulk contents of the vehicle to be unloaded via an attached conveyor belt or via the live floor alone, without having to remove the device from the vehicle.